Agreed, till you hit a problem that requires 10,000+ lines of code. I love Python to bits but for this one large website I am working on I wish it was written in C# Java or some other statically typed language.

When you have a large project I will always take the compile time checking that tends to resolve a lot of bugs over unit tests to verify the same thing. Especially when it comes to large re-factoring efforts.

One of the most important things programmers can learn is that you don't have to choose one language per project. Binding, say, Python and C++ in the same program can be very valuable (though it is not trivial, even with SWIG). Some code benefits from the simplicity, clarity, testability and huge standard library of the scripting language, and the remaining code gains performance and expressiveness to handle its greater complexity.